The Vasant Valley School Science Magazine

Quantum Computing

Quantum Computing

By Divvij Chandna

Technology is moving forward every day and we are now finding ways to make our lives faster and easier using this technology. As advancements are being made, our gadgets are becoming smaller, thinner and lighter. But there is a limit to how small an object can be, so what is the solution when this limit is reached? The answer to this is quantum computing.

Quantum computing is an emerging branch of computers that uses principles of quantum physics to help machinesperform complex tasks. Every chip or circuit in a computer consists of transistors, these are responsible for the processing power and speed of the devices. Hence, the more the transistors on a chip, the faster a gadget will function. According to Moore’s law (To read more about Moore’s law, visit:
http://sciencemag.vasantvalley.org/moores-law-and-its-current-challenge/), the number of transistors per square metre of an integrated chip doubles every year. Since the size of transistors has now reached a minuscule 1 nanometer, it is highly unlikely that Moore’s law will be followed in the next few years.

A transistor is the fundamental unit of any technological device and it contains only two states, 1 (on) and 0 (off), the memory unit that contains data about this state is known as a bit. Though the inability to make transistors any smaller is quite a disappointment, due to their tiny size, they obey certain laws of quantum physics which can lead to huge breakthroughs. One of the properties exhibited is quantum tunnelling, any particle, most likely an electron, passing through a transistor will not be obstructed by it, but it will tunnel through it. Hence, there are a large number of states
possible other than on and off, and this data is stored in a qubit. To explain this in Layman’s terms, imagine a ball lying on one side of a hill, this is when the transistor is off. The only other place the
ball can be is on the other side, where it is on, if it is placed anywhere on the hill, the ball will roll off. Due to quantum tunnelling, the ball can also be anywhere inside the hill now, and can even cross the hill, passing through it whether there is any physical barrier or not. This creates a problem as electrons, which make up electricity, can effectively tunnel through the transistor whether it is ‘on’ or ‘off’, making the transistor useless.

Instead, quantum computer scientists use ‘qubits’ ( the quantum version of a bit). Instead of a bit, which can only be 1 or 0, a qubit can have multiple more states, allowing it to store much more information and have a greater processing power in a much smaller space.

The processing of a system containing qubits is far ahead of anything we use today. Actually, 4 qubits is equivalent to 65,500 bits! This does not mean that our phones and computers while run at a much faster speed, they might actually be slower using qubits. But while performing complex tasks, quantum computers can be much more useful.

They can even break the strongest encryption in the world today and the data stored on these will also be impossible to hack and retrieve. Currently, quantum computing does have its drawbacks and there is still a lot of research to do in this field. There are very few people in this world who know how to create such tiny transistors and the materials required to do so are also very expensive. The chips of these computer need to be stored in temperatures close to absolute zero, which is a big challenge in itself. Hence, it will still be while before quantum computers become feasible and useful to a larger number of people.